1. Field of the Invention
The present invention relates to a lid device for opening and closing an opening of a storage structure.
2. Description of the Related Art
There are a variety of known lid devices for opening and closing openings of storage structures, but opening and closing operations of the lid devices sometimes impose, on a user, a burden which depends on the kind of storage structures. For example, a glove box for a vehicle is a kind of storage structure and mounted in a small-spaced passenger room. Therefore, a user needs to perform opening and closing operations of a lid body in a small space and sometimes finds it difficult. Under these circumstances, a lid device has been developed which is capable of opening and closing a lid body easily by driving automatically (For example, Japanese Unexamined Patent Publication No. H02-267038). In the lid device disclosed in this Japanese patent document, a motor starts upon a user manually applying a force to start an opening or closing operation of the lid body, and then the motor drives the lid body to be opened or closed. In such a lid device, an opening or closing operation of the lid body can be carried out by a simple operation of the user, without imposing a burden on a user. On the other hand, since the motor is expensive, there is a problem that production cost of the lid device increases.
It is assumed that production cost of the lid device can be reduced if the opening or closing operation of the lid body is driven by an urging member such as a spring instead of the motor. In this case, for example, if an urging force is accumulated by stretching or compressing the urging member in association with opening or closing the lid body, the accumulated urging force can drive at least part of the opening or closing operation of the lid body.
In general, a lid device is provided with a lock means and a lid body is locked in a closed position by the lock means. In opening the lid body, the lock means is operated so as to release the locked state of the lid body. In order to simplify the opening operation of the lid body, the lid body needs to be opened by a single operation of the lock means. Therefore, it is demanded that the lid device has a function of driving the opening operation of the lid body by an urging member at the same time as releasing the locked state of the lid body. By the way, the center of gravity of the lid body sometimes lies on the closing side of the lid body in a manner that depends on the shape or location of a storage structure. For example, when the storage structure is a glove box mounted on a vehicle and the vehicle is parked on a slope, the center of gravity of the lid body may lie on the closing side of the lid body. When the center of gravity of the lid body lies on the closing side of the lid body, a force to move to a closed position under its own weight is applied on the lid body and a large urging force is required to drive the opening operation of the lid body. Therefore, in this case, sometimes the lid body is not opened by a single operation of the lock means. When the lock means has a certain mechanism, sometimes the lid body is not only unopened but also locked again in a closed position.